Automatic boom control



Sept 7, 1965 H. H. wAsHBoND 3,204,794

AUTOMATIC BOOM CONTROL Filed Nov. 4, 1963 2 Sheets-Sheet l Sept. 7, 1965 H, H. wAsHBoND 3,204,794

AUTOMATIC BOOM CONTROL Filed Nov. 4, 1963 2 sheets-sheet 2 Eff United States Patent O 3,204,794 AUTOMATIC BUM CONTROL Harry H. Washhoud, Springfield, Ill., assigner to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Filed Nov. 4, 1963, Ser. No. 321,277 3 'Claims (Cl. 214-140) This invention relates to an automatic boom control wherein the valve for operating the boom controlling motor is automatically moved to its hold position when the boom has reached predetermined elevated and lowered positions.

Heretofore kickout devices have been provided for returning a control valve to a neutral or hold position when the boom of a loader is raised to a predetermined height. Such devices are desirable in that the operators hands are free for other functions while the boom is being raised. The present invention not only returns the valve for the boom controlling motor to a hold position when the boom is raised to a predetermined elevation, but also returns the valve to a hold position when the boom is lowered to a predetermined position With the Valve in its loat position.

It is an object of this invention to provide an automatic boom control wherein the valve for operating the boom controlling motor is automatically returned to its hold position from its raise and lloat positions when the boom has moved to its elevated position and lowered position, respectively.

It is a further object of this invention to provide an automatic boom control wherein the oat position of the valve for operating the boom controlling motor is detented and wherein the nondetented lower position of the valve is intermedliate the hold and float positions, thus permitting the operator to move the valve to its lower position to power down on the material handling attachment connected to boom subsequent to the valve having been kicked out of its detented float position.

It is a further object of this invention to provide an atuomatic boom control for a tractor shovel which is comprised of mechanical elements insuring good reliability, low cost manufacture and easy servicing.

These and other objects of this invention will be apparent to those familiar with the art when the following description is read in conjunction with the drawings, in which:

FIG. l is a side view of a tractor shovel in which my invention is incorporated;

FIG. 2 is a section view of the Valve for controlling the double acting hydraulic jack employed for raising and lowering the shovel;

FIG. 3 is a top view of the control llinkage for the valve illustrated in FIG. 2;

FIG. 4 is a side View of the valve operating linkage shown in FIG. 3; and

FIG. 5 is a side view similar to FIG. 4 but showing the control valve in its detented oat position.

Referring to FIG. l, the illustrated tractor shovel 11 is comprised of a tractor 12 with a frame 14 on which a loader 13 is mounted. The loader 13 includes a boom 16 pivotally connected at its rear end to the frame 14 of the tractor on a transverse pivot aXis 17 by a pin 15. A material handling attachment in the form of a bucket 18 is pivotally connected to the front end of the boom 16 by pin 19 and an adjusting linkage including link 21, lever 22 and jack 23 is provided for pivoting the bucket 18 about pin 19 between carrying and dumping positions. The boom is raised and lowered by a fluid motor in the form of a double acting hydraulic jack 26 pivotally connected at its opposite ends to the frame 14 and boom 16, respectively. A control valve 31 for operating the jack 26 is mounted on top of a fluid reservoir 32. The valve ICC 31 is operated by control means 33 at the operators station. v

Referring to FIG. 2, the control valve 31 includes a flow control element in the form of a spool 36 which 1s reciprocably mounted in a bore 37 of a valve housing 38.

. The valve 31 is of the open center type and has raise,

lower, hold and float positions. In the hold position illustrated in FIG. 2, fluid delivered through inlet passage 39 flows to reservoir return passage 41. In the neutral or hold position, and jack supply ports 42, 43 are blocked. The ports 4243 are connected to hoses 44, 46, respectively, which in turn are connected to jack 26, as shown in FIG. l. A centering means 51 is provided to resiliently urge the control valve spool 36 to its hold position, as shown in FIG. 2. The centering means 51 does not exert suicient force to urge the spool 36 out of its detented raise and iloat positions. The detent means 56 includes a series of circumferentially spaced balls 57, wedging members 58, 59, a spring 61 and an end portion 62 on spool 36 which has recessed portions 63 and 64 in axially spaced relation to one another. The end portion 62 has a slightly tapered conical portion 67 which gradually increases in diameter from its left terminus to the cylindrical portion 68. The juncture of surfaces 67, 68 form a slight angular edge 69 winch provides feel for the operator when the valve spool 36 is moved to a position where the balls 57 ride over the edge, which position is the lower position of the spool 36.

Referring to FIGS. 3 and 4, a manual control member in the form of a lever 71 is pivotally connected by a pin 74 to a pair of brackets 72, 73 extending from the reservoir 32. The control lever 71 has a pair of arms 76, 77 rigidly secured thereto, arm 77 being connected tothe llow control element 36 through a bell crank 78 and links 79, 81. Bell crank 78 is pivotally connected by a pin 83 to a bracket 82 on the reservoir 32.

Motion responsive means 86 are provided between the flow control element 36 and the boom 16 for automatically moving the flow control element out of its detented raise and float positions toward its hold position when the boom is moved by the jack 26 to predetermined elevated andflowered positions, respectively. The motion responsive means 86 includes a rst thrust transmitting member in the form of a lever 87 pivoted by pin 88 t-o the frame 14 and a second thrust transmitting member 89 pivotally connected to arm 76 of the control lever 71. A link 91 pivotally interconnects the lever 87 to the boom 16. The lever 87 has a thrust transmitting head port-ion 92 which slidably engages the rod 93 of member 89. A pair of spaced abutments 94, 96 are secured to the rod 93, abutment 96 being engaged by the thrust transmitting member 87 when the boom is moved by the jack 26 to its elevated position and abutment 94 being engaged by member 87 when the boom is moved to i-ts lowered position with the flow control element 36 in its lloat position.

Referring to FIG. 5, the ilow control element 36 is shown in its float position and it will be noted that in this position the ports 42, 43 are open to the reservoir return passage 41. In the oat position of the spool 36 the balls 57 of the detent means engage recess 64 and contro'l lever 71 occupies its extreme forward position as illustrated. The boom, as illustrated in FIG. 5, has just reached its predetermined lowered position wherein the thrust transmitting member 87 engages abutment 94 which results in the spool 36 being moved to the right sufficiently to cause balls 57 to cam out of the groove 64. When this occurs the centering means 51 will move the valve through the lower position to the hold position illustrated in FIG. 2. When the contr-ol valve is moved `to its hold position, lever 71 will move to its hold position as illustrated by the dash lines 71' in FIG. 5, and

abutment 94 will moveto the position illustrated by dash lines 94' in FIG. 5. Thus, after the automatic-kickout mechanism 86 has moved the control valve out of its detented tloat position through engagement of the thrust transmitting member 87 and abutment 94, the operator can move the control valve to its lower position by virtue of the spacing of the abutment member 94 and thrust transmitting member 87 in this position. Accordingly, the operator can power down on the shovel to effect digging or excavating operation after the control valve spool 36 has been kicked out of its detented float position.

From the foregoing description, it is apparent that this invention provides additional operator convenience which saves operator time in lthat the control valve for the boom jack is automatically returned to a hold position when the loader boom reaches a predetermined elevated position and a predetermined lowered position, withthe valve -in float position. Also my automatic boom control is `designed so that the operator can move the boom control valve to its lower position, which is not detented, to power down on the shovel after the kick out mechanism hasl returned the valve to its hold position from` its 'oa-t position. v

Having now particularly described and ascertained the nature of my said invention and the manner in which it is to be performed, I declare that what I claim is:

A1. In combination with a tractor,

a longitudinally extending boom pivoted at its'rear end on said tractor for vertical swinging movement about a transverse pivot axis,

-a material handling attachment secured to the front end of said boom,

a iluid motor interconnected between said tractor and boom for moving the latter about said transverse pivot axis between elevated and lowered positions,

a con-trol valve on said tractor for said motor including a shift-able ilow control element having spaced raisev and iloat positions, a hold position between said raise 'and iloat position and a lower position between said hold and lloat position,

i r detent means for rcleasably holding said element in said raise and float positions only and f centering means operative to move said element to said hold position when moved out of said detented raise and hold positions, and motion responsive means positioned between said ilo-w control element and broom for automatically moving said ow control element out of its detented raise andlloat positions toward said hold position when said boom is moved to predetermined elevated and lowered positions, respectively, said control element being shiftable to said lower position immediately after its being automatically moved out of its float position without its incurring interference with said motion responsive means.

2. The structure set forth in claim 1 wherein said motion responsive means includes a first thrust transmitting member'connected to said boom, a second thrust transmitting member connected to said How control element and a pair of spaced abutments formed on one of said thrust transmitting members and engageable, respectively, by the other of said thrust transmitting members when said boom is moved by said motor to said predetermined elevated position and when said boom moves to said predetermined lowered position with said ilow control element in its float position.

3. The structure set forth in claim 2 wherein said ow control element is movable to its lower position after having been moved out of its oat position by said motion responsive means thereby permitting the boom to be moved below said predetermined lowered position.

References Cited by the Examiner l' UNITED STATES PATENTS 3,035,710 5/62 Pohl 212-8 3,045,845 7/62 Hackett et al 214-140 IrIUGO O. SCHULZ, P'rrvnary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,204,794 September 7, 1965 Harry H. Washbond It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected-as shown below:

Column 4, line S, "hold" should read float Signed and sealed this 26th day of August 1969.

SEAL) tteSt;

lward M. Fletcher, Jr. JR.

ttesting Officer Commissioner of Patents 

1. IN COMBINATION WITH A TRACTOR, A LONGITUDINALLY EXTENDING BOOM PIVOTED AT ITS REAR END ON SAID TRACTOR VERTICAL SWINGING MOVEMENT ABOUT A TRANSVERSE PIVOT AXIS, A MATERIAL HANDLING ATTACHMENT SECURED TO THE FRONT END OF SAID BOOM, A FLUID MOTOR INTERCONNECTED BETWEEN SAID TRACTOR AND BOOM FOR MOVING THE LATTER ABOUT SAID TRANSVERSE PIVOT AXIS BETWEEN ELEVATED AND LOWERED POSITIONS, A CONTROL VALVE ON SAID TRACTOR FOR SAID MOTOR INCLUDING A SHIFTABLE FLOW CONTROL ELEMENT HAVING SPACED RAISE AND FLOAT POSITIONS, A HOLD POSITION BETWEEN SAID RAISE AND FLOAT POSITION AND A LOWER POSITION BETWEEN SAID HOLD AND FLOAT POSITION, DETENT MEANS FRO RELEASABLY HOLDING SAID ELEMENT IN SAID RAISE AND FLOAT POSITIONS ONLY AND CENTERING MENS OPERATIVE TO MOVE SAID ELEMENT TO SAID HOLD POSITION WHEN MOVED OUT OF SAID DETENTED RAISE AND HOLD POSITION, AND MOTION RESPONSIVE MEANS POSITIONED BETWEEN SAID FLOW CONTROL ELEMENT AND BOOM FOR AUTOMATICALLY MOVING SAID FLOW CONTROL ELEMENT OUT OF ITS DETENTED RAISE AND FLOAT POSITIONS TOWARD SAID HOLD POSITION WHEN SAID BOOM IS MOVED TO PREDETERMINED ELEVATED AND LOWERED POSITIONS, RESPECTIVELY, A SAID CONTROL ELEMENT BEING SHIFTABLE TO SAID LOWER POSITION IMMEDIATELY AFTER ITS BEING AUTOMATICALLY MOVED OUT OF ITS FLOAT POSITION WITHOUT ITS INCURRING INTERFERENCE WITH SAID MOTION RESPONSIVE MEANS. 